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Deciphering invasion routes from molecular data is crucial to understanding biological invasions, including identifying bottlenecks in population size and admixture among distinct populations. Here, we unravel the invasion routes of the invasive pest Drosophila suzukii using a multi-locus microsatellite dataset (25 loci on 23 worldwide sampling locations). To do this, we use approximate Bayesian computation (ABC), which has improved the reconstruction of invasion routes, but can be computationally expensive. We use our study to illustrate the use of a new, more efficient, ABC method, ABC random forest (ABC-RF) and compare it to a standard ABC method (ABC-LDA). We find that Japan emerges as the most probable source of the earliest recorded invasion into Hawaii. Southeast China and Hawaii together are the most probable sources of populations in western North America, which then in turn served as sources for those in eastern North America. European populations are genetically more homogeneous than North American populations, and their most probable source is northeast China, with evidence of limited gene flow from the eastern US as well. All introduced populations passed through bottlenecks, and analyses reveal five distinct admixture events. These findings can inform hypotheses concerning how this species evolved between different and independent source and invasive populations. Methodological comparisons indicate that ABC-RF and ABC-LDA show concordant results if ABC-LDA is based on a large number of simulated datasets but that ABC-RF out-performs ABC-LDA when using a comparable and more manageable number of simulated datasets, especially when analyzing complex introduction scenarios.

All terrestrial ectotherms are constrained to some degree by their thermal environment and the extent to which they can behaviorally buffer variable thermal conditions. New biophysical modeling methods (NicheMapR) allow the calculation of the body temperature of thermoregulating animals anywhere in the world from first principles, but require detailed observational data for parameterization and testing. Here we describe the thermoregulatory biology of marching bands of the desert locust, Schistocerca gregaria, in the Sahara Desert of Mauritania where extreme heat and strong diurnal fluctuations are a major constraint on activity and physiological processes. Using a thermal infrared camera in the field, we showed that gregarious nymphs altered the microhabitats they used, as well as postural thermoregulatory behaviors, to maintain relatively high body temperature (nearly 40°C). Field and laboratory experiments demonstrated that the preferred body temperature accelerated digestive rates. Migratory bands frequently left foraging sites with full guts before consuming all vegetation and moved to another habitat before emptying their foregut. Thus, the repertoire for behavioral thermoregulation in the desert locust strongly facilitates foraging and digestion rates, which may accelerate developmental rates and increase survival.We used our data to successfully parameterize a general biophysical model of thermoregulatory behavior that could capture hourly body temperature and activity at our remote site using globally available environmental forcing data. This modeling approach provides a stronger basis for forecasting thermal constraints on locust outbreaks under current and future climates.

Knowing the phylogeographic structure of invasive species is important for understanding the underlying processes of invasion. The micromoth Phyllonorycter issikii, whose larvae damage leaves of lime trees Tilia spp., was only known from East Asia. In the last three decades, it has been recorded in most of Europe, Western Russia and Siberia. We used the mitochondrial cytochrome c oxidase subunit I (COI) gene region to compare the genetic variability of P. issikii populations between these different regions. Additionally, we sequenced two nuclear genes (28S rRNA and Histone 3) and run morphometric analysis of male genitalia to probe for the existence of cryptic species. The analysis of COI data of 377 insect specimens collected in 16 countries across the Palearctic revealed the presence of two different lineages: P. issikii and a putative new cryptic Phyllonorycter species distributed in the Russian Far East and Japan. In P. issikii, we identified 31 haplotypes among which 23 were detected in the invaded area (Europe) and 10 were found in its putative native range in East Asia (Russian Far East, Japan, South Korea and China), with only two common haplotypes. The high number of haplotypes found in the invaded area suggest a possible scenario of multiple introductions. One haplotype H1 was dominant (119 individuals, 67.2%), not only throughout its expanding range in Europe and Siberia but, intriguingly, also in 96% of individuals originating from Japan. We detected eight unique haplotypes of P. issikii in East Asia. Five of them were exclusively found in the Russian Far East representing 95% of individuals from that area. The putative new cryptic Phyllonorycter species showed differences from P. issikii for the three studied genes. However, both species are morphologically undistinguishable. They occur in sympatry on the same host plants in Japan (Sendai) and the Russian Far East (Primorsky krai) without evidence of admixture.

The alfalfa weevil Hypera postica , native to the Western Palearctic, is an invasive legume pest with two divergent mitochondrial clades in its invading regions, the Western clade and the Eastern/Egyptian clade. However, knowledge regarding the native populations is limited. The Western clade is infected with the endosymbiotic bacteria Wolbachia that cause cytoplasmic incompatibility in host weevils. Our aim was to elucidate the spatial genetic structure of this insect and the effect of Wolbachia on its population diversity. We analyzed two mitochondrial and two nuclear genes of the weevil from its native ranges. The Western clade was distributed in western/central Europe, whereas the Eastern/Egyptian clade was distributed from the Mediterranean basin to central Asia. Intermediate mitotypes were found from the Balkans to central Asia. Most Western clade individuals in western Europe were infected with an identical Wolbachia strain. Mitochondrial genetic diversity of the infected individuals was minimal. The infected clades demonstrated a higher nonsynonymous/synonymous substitution rate ratio than the uninfected clades, suggesting a higher fixation of nonsynonymous mutations due to a selective sweep by Wolbachia . Trans-Mediterranean and within-European dispersal routes were supported. We suggest that the ancestral populations diversified by geographic isolation due to glaciations and that the diversity was reduced in the west by a recent Wolbachia -driven sweep(s). The intermediate clade exhibited a body size and host plant that differed from the other clades. Pros and cons of the possible use of infected-clade males to control uninfected populations are discussed.

Male mating harassment may occur when females and males do not have the same mating objectives. Communal animals need to manage the costs of male mating harassment. Here, we demonstrate how desert locusts in dense populations reduce such conflicts through behaviors. In transient populations (of solitarious morphology but gregarious behavior), we found that nongravid females occupied separate sites far from males and were not mating, whereas males aggregated on open ground (leks), waiting for gravid females to enter the lekking sites. Once a male mounted a gravid female, no other males attacked the pair; mating pairs were thereby protected during the vulnerable time of oviposition. In comparison, solitarious locusts displayed a balanced sex ratio in low-density populations, and females mated irrespective of their ovarian state. Our results indicate that the mating behaviors of desert locusts are density dependent and that sex-biased behavioral group separation may minimize the costs of male mating harassment and competition.

Insects harbor a diversity of microbes that are known to affect their host’s response to biotic and abiotic stressors. This is important in the context of climate change and human-caused habitat alterations, during which drastic changes are so rapid that organisms have little time to adapt. Symbionts often accompany invading species, and might play a role in the success or failure of insect invasions. Yet, few studies have examined the evolutionary dynamics and role of gut-associated symbionts at different stages of an insect invasion. We focus on the family Tephritidae (Diptera), which comprises many invasive pest species, and examine how gut-associated bacteria might influence their invasion process based on literature review. Based on our review, we first summarize the prevalence and diversity of gut-associated bacteria harbored by tephritid species. Next, we highlight how those gut communities may influence the fitness of invasive species during the colonization process. We conclude that gut-associated symbionts are highly flexible, and can respond rapidly to changes in biotic and abiotic factors and compensate for limited adaptive capacities of their hosts to counteract these stressors, through changes in the taxonomic composition or prevalence of the community. However, bacteria of Enterobacteriaceae are dominant as well as constitute constant and stable populations in fruit fly gut under different environmental stressors. Our review reveals that this family represents a key bacteria group in all studied tephritid species. This review indicates that knowledge on symbiont–insect interactions is crucial for understanding the success of insect invasion and it should be considered in risk analyses, impact modeling and optimizing invasive pest management.

Introduction. L’anacardier (Anacardium occidentale L.) est surtout cultivé pour la production de l’amande ou noix de cajou mais aussi pour le pseudofruit. Les insectes nuisibles à cette plante ont été étudiés au Pérou où celui-ci est consommé. Matériel et méthodes. Des prélèvements ont été réalisés de 1998 à 2005 dans différentes localités du département de Loreto en Amazonie péruvienne afin d’identifier les insectes ravageurs de l’anarcadier. Des observations de terrain et des élevages au laboratoire ont permis de caractériser leurs dégâts et des éléments de la bio-écologie pour chacun de ces insectes. Résultats. Sept espèces d’insectes ont été identifiées, qui commettent des dommages notables : cinq espèces s’attaquent au pseudofruit : Acanthocephala parensis (Hemiptera : Coreidae), Anastrepha obliqua (Diptera : Tephritidae), Conotrachelus sp. (Coleoptera : Curculionidae), Trigona amalthea et T. amazonensis (Hymenoptera : Apidae). L’espèce Aphis gossypii (Hemiptera : Aphididae) infeste l’inflorescence ainsi que le fruit. Les larves de Macrocopturus cf. tristis (Coleoptera : Curculionidae) se développent dans les bourgeons et les jeunes rameaux. Trois espèces parmi celles qui ont été identifiées sont de nouveaux ravageurs qui n’avaient pas été encore signalés. Sept espèces d’importance secondaire ont également été observées. Conclusion. Compte-tenu du potentiel que représente la production de pomme cajou et du développement possible de la culture de l’anacardier en Amazonie péruvienne, une étude plus approfondie des insectes nuisibles à cette production est souhaitable. Introduction. The cashew (Anacardium occidentale L.) is mainly grown for the production of cashew nuts, but also for the pseudofruit. The insect pests of the plant were studied in Peru, where this fruit is consumed. Materials and methods. Samples were taken from 1998 to 2005 in different localities of the department of Loreto in the Peruvian Amazon to identify insect pests of cashew. Field observations and laboratory farms were used to characterize the damage caused by each insect. Results. Seven species of insects cause significant damage: five species attack the pseudofruit: Acanthocephala parensis (Hemiptera: Coreidae), Anastrepha obliqua (Diptera: Tephritidae), Conotrachelus sp. (Coleoptera: Curculionidae), Trigona amalthea and T. amazonensis (Hymenoptera: Apidae). The pest Aphis gossypii (Hemiptera: Aphididae) infests the inflorescences, buds and young fruit. The larvae of Macrocopturus cf. tristis (Coleoptera: Curculionidae) develop in buds and young shoots. Three new species are pests which have not yet been reported. Conclusion. Given the potential of the cashew apple production and the possible development of the culture of the cashew tree in the Peruvian Amazon, a more extensive study of the insect pests is desirable. Introducción. El anacardo (Anacardium occidentale L.) se cultiva principalmente para la producción de almendras o castañas de cajú, sino también para el pseudofruto. Los insectos plagas de la planta fueron estudiados en el Perú, donde se consume. Materiales y métodos. De 1998 a 2005 se tomaron muestras en diferentes localidades del departamento de Loreto en la Amazonía peruana para identificar las plagas de los anacardos. Las observaciones de campo y de laboratorio se utilizaron para caracterizar el daño a cada uno. Resultados. Siete especies de insectos cometen un daño significativo: cinco atacan el pseudofruto: Acanthocephala parensis (Hemiptera: Coreidae), Anastrepha obliqua (Diptera: Tephritidae), Conotrachelus sp. (Coleoptera: Curculionidae) Trigona amalthea y T. amazonensis (Hymenoptera: Apidae). Aphis gossypii (Hemiptera: Aphididae) infesta la inflorescencia, el fruto joven y los brotes. Las larvas de Macrocopturus cf. tristis (Coleoptera: Curculionidae) se desarrollan en los brotes y ramas jóvenes. Tres especies son nuevos reportes para el cultivo. Conclusión. Dado el potencial de la producción de manzanas de marañón y el posible desarrollo de la cultura del anacardo en la Amazonía peruana, un estudio más profundizado de los insectos plagas es deseable.

The healthy lifestyle and appropriate nutrition are stressed nowadays. New foodstuffs are still investigated with the aim to improve the diet and conduce to a better health state of the population. Pseudocereals (amaranth, buckwheat, quinoa) are convenient for this purpose. Their high nutritious and dietary quality meets the demands of the food industry and consumers. Our article deals with quinoa, a commodity from the Andean region, because quinoa is a good source of essential amino acids such as lysine and methionine. Quinoa contains relatively high quantities of vitamins (thiamin, vitamin C) and minerals.

The predatory bug Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important biological control agent in Asia that is often released on field crops and in greenhouses to control pests on vegetable and ornamental plants. This study compared the developmental and reproductive performance of O. sauteri on monotypic diets of four aphid species, western flower thrips, and two-spotted spider mite. Thrips emerged as the optimal prey type, consistent with findings for many other Orius spp. A diet of Frankliniella occidentalis (Pergande) yielded the fastest development, largest adult body size, shortest pre-oviposition period, and highest fecundity and longevity. Tetranychus urticae (Koch) was the next most suitable prey by most performance measures. Among aphids, Myzus persicae (Sulzer) was the most suitable and Aphis gossypii Glover the least suitable, with Aphis craccivora Koch and Megoura japonica (Matsumura) intermediate. Female O. sauteri were larger than males and female body mass varied more with prey type than did that of males. Despite the variation in performance among prey, all prey species yielded equally good juvenile survival and none would be expected to negatively impact the numerical response of O. sauteri in biological control applications where these arthropods form part of the prey complex.